Loud-speaking device for wireless



Juhe 30, 1925. 11,543,718

Filed July 30. 1920 WITNESSES: INVENTOR Z0. W fialohfill/larbwy ATTORNEY Patented dune dill, i925.

RALPH a. manner,

SYLVAINIA.

F EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO WEST- INGHOUSE ELJEUTRIC dz MANUFACTURING COMPANY, A CORPORATION OF PENN-.

oon-ermine DEVICE FOR WIRELESS.

Application filed July so, 1920. Serial No. 400,265.

To all wimm it may concern: I

Be it known that I, RALPH E. MARBURY,

a citizen of'the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvementin Loud-Speaking Devices for Wireless, of which the following is a specification.

My invention relates to telephones and more especially to such instruments in which a horn is employed for amplifying the sound vibrations."

A particular object of my invention is to provide a loud-speaking telephone, especially in connection graphic work.

Heretofore, the telephone transmitters employed have not made use'o'f all the possibilities that are to be derived from a strong magnetic field acting upon the diaphragm mechanism.

A further object of the invention, therefore, is to provide an ironclad magnetic circuitfor the fixed magnetic field of a telephone transmitter. Y r

A further object of my invention is to provide a very sensitive telephone transmitter or receiver. H

Other objects and advantages of my invention will necessarily follow from an inspection of the drawings, when taken in conjunction with the accompanying description, and will, moreover, be made a part of the claims. 7L

Figure 1 is a View, partially in elevation and partially in longitudinal section, of an embodiment of my lnvention; Fig. 2 is a horizontal'sectional View taken on line II- II of Fig. 1.

In providing a magnetic circuit for a main exciting coil 1, which is tobefed by a direct-current source (not shown) in the usual manner, a cup-shaped member 2 is provided, forming part of a yoke having a central core member 3 acting in co-operation with a boss or button 4: mounted integral with a cover 5, forming part of the yoke system. It will be observed that the central core member 3 is spaced from the boss 4 sufficiently to provide a working air ga for an armature or reed-like member 6 a fixed to a stud 7 that is rigidly connected to the cover 5 by means of a screw 8. The

, reed 6. 1s preferably attached, by means of a pluralityof screws 9, to

withv wireless telethe sup orting stud 7. p

Mounted about the reed is an exciting I coil 10 fed by means of leads 11 from a suitable receiving oircuit. Such receiving circuit is indicated diagrammatically in Fig. 1 by -means of a transformer 12 fed from a radio-receiver set. The main exciting coil 1, on the other hand, isfed by means of leads 13 from any suitable direct-current source well known to the art. The cover 5 is preferably attached by means of machine screws 14. Upon such cover is likewise at tached a bridge-piece 15 by means of'the screws 16 or the like. Such bridge-piece is suitably threaded at 17 for the attachment of an amplifying horn;

The cover 5 and boss 4 are drilled for the insertion of a pin 18 connecting the reed 6 with a diaphragm 19 upon which latter the sound waves are either caused to impinge orby means of which the sound waves are set up by virtue of the alternating character of the current feeding the telephoneexciting coil 10. The diaphragm 19 is 'mounted over a recess 2min the cover plate.

If desired, the diaphragm 19 (as shown) may be suitably clampedat its periphery to the cover plate 5 by means of the bridgepiece 15. a

In the operation of the device, the main coil 1 is suitably fed by a direct-current source so as to form a north pole at the end of the central pole member opposite the boss or button 4 integral with the cover plate 5. Since the cover plate and boss are likewise of magnetic material, the surface of the boss assumes an opposite polarity. The magnetic circuit is thereafter completed througn the cup-shaped member 2, likewise of magnetic material. The reed member 6 being mounted with the speech-controlled coil 10 thereon, alternately becomes magnetized north and south at the extreme ends of the reed. Thus, when the speech current feeding the coil is in one direction, the reed and,

therefore the diaphragm 19 will move in a particular direction, whereas, when the speech current is in the opposite direction, the reed, being oppositely polarized, will be drawn toward the central pole 3 of the magnetic system. In view of the fact that the ma netic field between the boss and pole is made exceedingly strong, any small variationin the current exciting the coil having an opening said air-gap,

will produce a very considerable movement of the diaphragm and the reed. s

It will be seen, therefore, that'y iiy means of my invention,

mechanism.

Having disclosed the nature of my invention, what I claimis:

1 In combination with magnetic means including two pole-pieces with an airap therebetween, a member disposed wit in said air-gap and movable bodily toward and away fromthe respective pole-pieces, one of said pole-pieces having an opening thereinterminating in said air gap, a diaphragm spaced from the outer face of said Iast mentioned pole-piece,'a connecting member extending within said opening and connecting said diaphragm and said movable member, and an electric circuit including a coil operatively associated with said movable member said coil being outside said air gap.

2. In combination with a pairof vpolepieces having an air-gap therebetween, means for producing a magnetic flux from one pole-piece to the other across said airgap, a reed fixed to a point outside of said air-gap and including a magnetizable portion extending withinsaid air-gap and movable bodily toward and spective pole-pieces, one of said pole-pieces therein terminating in said air gap, a diaphragm spaced from the outer face of said last-mentioned polepiece, a connecting member extending within said opening and connecting said diaphragm and said vibratory portion, and an electric circuit including a coiloperatively associated with said reed.

3. In combination with a yoke member of cup shape, a substantially centrally-disposed core member rigidly connected to said yoke,-

means for producing a unidirectional magnetic flux in said cup and core members, a cover for said cup-shaped member forming apart of said yoke, the said core member being axially spaced from said cover to form an air-gap, a movable member disposed in and an electric circuit including a coil outside said air-gap carrying variable currents corresponding to flux-changes in said movable member. p

4. In combination with a yoke member of cup shape, a substantially centrally-disposed core member rigidly connected to said yoke,

' means for producing I am able to produce a. most efficient speech-reproducing device as well as a most sensitive speech-transmitting having one portion dis able bodily away. from the re.

a unidirectional mag netic flux 1n said cup and core members, a cover for said oup-sha ed member forming a part of said yoke, t c said core member 'being spaced from said cover to form an magnetizable member osed within said airgap and movable bodily in a substantially rectilinear direction toward and away from the respectivepole-pieces and having another portion secured to a point/ outside of said air-gap, and a coil encircling said movable member, said coil carrying variable currents corresponding to flux-changes in said movable member.

5. In combination with a yoke member of cup shape, a substantially centrally-disposed core member rigidly connected to said yoke, means for producing a unidirectional magnetic flux in said'cup and core members, a cover for'said cup-shaped member forming apart of said yoke, the said core member being spacedfrom said cover to form an airgap, a reed fixed to a point outside of said air-gap and including a magnetizable portion extending Within air-gap, a vibratory said air-gap and movtoward and away from the respective pole-pieces, and an electric circuit including a coil carrying variable currents corresponding to flux-changes in said movable member, said movable member being mounted. substantially in the axis of said coil.

6. In combination with a yoke member of cup shape, a substantially centrally-disposed core vmember rigidly connected to said'yoke, means for producing a' unidirectional magnetic flux in said cup and core members, a cover for said cup-shaped member forming a part of said yoke, the said core member being spaced from said cover, said cover having a substantially centralopening extending adjacent to said core member, a diaphragm spaced from the outer face of said cover, a movable member disposed in the space between said cover and said core member, a connecting member ex tending Within said opening and connecting said diaphragm and said movable member,

and an electric circuit including a coil magnetically associated with said movable member.

In testimony whereof, I have hereunto subscribed my name this 17th day of July,

RALPH E. MARBURY. 

